The present invention relates to a liquid ejecting head unit and a manufacturing method for the liquid ejecting head unit, wherein liquid (print liquid such as ink) is ejected onto a print medium to effect printing.
Generally, the liquid ejecting head includes a plurality of fine ejection outlets for ejecting the printing liquid, liquid flow paths in fluid communication with the respective ejection outlets, and ejection energy generating elements disposed in the respective liquid flow paths, wherein the ejection energy generating elements are supplied with driving signals corresponding to the information to be printed to apply ejection energy to the printing liquid in the liquid flow path corresponding to the ejection energy generating element, by which the liquid is ejected through the ejection outlet as a droplet to effect printing.
Such a liquid ejecting head includes an element substrate on which a plurality of ejection energy generating elements which are formed with high precision using semiconductor manufacturing technique are disposed, a plurality of liquid flow path grooves in fluid communication with the plurality of ejection outlets, a common liquid chamber in fluid communication with the liquid flow path, and a top plate having a liquid receiving opening. Additionally, such a liquid ejecting head includes a container chip (container in the form of a chip) provided with supply passages formed therein to supply the liquid to the common liquid chamber in the top plate. The path through which the liquid is supplied the supply passage is in fluid communication withe a supply passage having the same width of the flow path.
Recently, the demands for such a liquid ejection printing apparatus are for increase of the printing speed, downsizing, productivity and inexpensiveness. As the liquid ejecting head which is carried on a carriage, the same demands apply. Among them, one of the factors relating to the increase of the printing speed is increase of the amount of the supply of the liquid. When the printing speed is increased, the amount of print per unit time increases, with the result that liquid consumption also increases. Therefore, the increase of the amount of the liquid supply to the liquid flow path is required. In order to increase the amount of the liquid supply, a liquid ejecting head unit may be provided with a second common liquid chamber which is provided with a communicating portion in fluid communication with the supply passage of the container chip to provide sufficient capacity of the liquid, but with such a structure, it is necessary to communicate the supply passage of the container chip with the communicating portion of the second common liquid chamber.
For providing fluid communication between the supply passage of the container chip and the second common liquid chamber, communicating portion of the second common liquid chamber and the supply passage of the container chip are connected by engagement, or the opening of the supply passage of the container chip and the opening of the second common liquid chamber are abutted to each other.
Referring first to FIGS. 76 and 77, there is shown a connection between the container chip and a unit frame having the second common liquid chamber when the opening of the supply passage of the container chip and the opening of the second common liquid chamber are abutted to each other.
The opening of the supply passage of the container chip and the opening of the second common liquid chamber have substantially the same diameter.
FIG. 76 is a sectional view of the container chip and the unit frame which are fastened with each other by screws.
The container chip end surface 801, having the opening, of the supply passage 805 of the container chip 800 is perpendicular to a direction 806 of flow of the print liquid which occurs in the supply passage 805 after the connection between the container chip 800 and the unit frame 807. Similarly, the abutment surface 803 of the second common liquid chamber to which the container chip end surface 801 is abutted is also perpendicular to the print liquid flow direction 806. Where the container chip end surface 801 and the second common liquid chamber abutment surface 803 are perpendicular to the print liquid direction 806, the container chip 800 and the unit frame 807 are fixed to each other after the container chip end surface 801 and the second common liquid chamber abutment surface 803 are abutted to each other in a direction of arrow D such that container chip end surface 801 and the second common liquid chamber abutment surface 803 do not interfere to each other.
FIG. 77 is a sectional view of the container chip and the unit frame which are fixed to each other by welded boss.
The container chip end surface 901 of the container chip 900 and the second common liquid chamber abutment surface 903 abutment surface 903 are perpendicular to the print liquid flow direction 906 similarly to the case of FIG. 76. On the upper surface of the unit frame 907, there is formed a welded boss 904 projected in an inclined direction, and the container chip 900 has an engaging hole 904 into which the welded boss 904 is fitted.
In the connection between the container chip 900 and the unit frame 907, the container chip 900 is moved toward the unit frame 907 in the direction indicated by an arrow E, and the welded boss 904 is inserted into the engaging hole 904, and container chip end surface 901 and second common liquid chamber abutment surface 903 are abutted to each other obliquely while using the welded boss 904 as a guide. Then, free end portion or leading end portion of the welded boss 904 projected out through the engaging hole 905, the container chip 900 and the unit frame 907 are fixed.
However, in providing fluid communication between the supply passage and the second common liquid chamber, the following problems may arise.
When the engagement between the supply passage and the second common liquid chamber is used, a difference results between the cross-sectional areas of the passages of the fitting part and the fitted part.
If the cross-sectional area of the passage abruptly changes at the end portion of the engaging part, a flow passage loss occurs in the flow of the print liquid, which may be against the increase of the supply amount of the liquid.
With the engaging or fitting structure, the size of receiving side member has to be larger than the entering side member, which is against the downsizing of the liquid ejecting head unit
In order to avoid such problems resulting from engagement, the abrupt change of the cross-sectional area of the passage can be avoided by abutting the opening of the supply passage and the opening of the second common liquid chamber having the same cross-sectional area of the passages, as shown in FIGS. 76 and 77.
However, when the opening end surface which is substantially perpendicular to the wall surface of the supply passage of the container chip and the opening end surface of the unit frame are abutted to each other, it is necessary to bring them into abutment to each other in an inclined direction to avoid interference to each other, when they are aligned with each other. In the aligning operations when the welded boss and the engaging hole are engaged with each other, the prior positioning is required to be strict with the result of lower productivity. Where they are press-contacted, or then are banded by filling material to prevent leakage of the liquid through the abutted portion between the end surface of the container chip and the end surface of the second common liquid chamber or to prevent introduction of the gas from the outside therethrough, sufficiently large thicknesses are required adjacent the end surface of the container chip and the end surface of the unit frame, which will add difficulty in downsizing.
Accordingly, it is a principal object of the present invention to provide a liquid ejecting head unit and a manufacturing method for the liquid ejecting head unit wherein the printing speed is high
It is another object of the present invention to provide a liquid ejecting head unit and manufacturing method for the liquid ejecting head unit wherein the liquid ejecting head unit can be downsized.
It is a further object of the present invention to provide a liquid ejecting head unit and a manufacturing method for the liquid ejecting head unit wherein the productivity of the liquid ejecting head unit can be improved.
When the filling material is used, the following problems may arise. A filling material of silicone rubber or the like generally exhibits a property of transmitting gas, and therefore, the ambient air may enter the flow path for the print liquid through the filling material with the result of bubbles produced in the flow path If the bubble is present in the flow path for the print liquid, the print liquid may be dried with the result of coagulation. When a coagulated matter is produced in the print liquid downstream of a porous member, the coagulation is liable to directly enter the liquid ejecting head with the possible result of clogging of the nozzle of the chip head.
Therefore, when the printer is operated after long term rest, or In order that bubbles produced in the flow path of the print liquid during a long term rest, a refreshing operation is carried out to forcedly suck the print liquid out through the nozzle of the chip head, thus filling the print liquid flow path with the print liquid. However, the print liquid consumed by such refreshing operation is not used but is wasted, the usage efficiency of the print liquid lowers if the refreshing operation is too frequent, with the result of running cost.
Where the porous member is perpendicular to the direction of the print liquid flow, the bubble tends to stagnate at the center of the print liquid flow path downstream of the porous member.
With the growing of the stagnated bubble, they expands in the horizontal direction with the result of clogging of the flow path at the lower side of the porous member. Then, the supply passage of the print liquid is blocked by the bubble, with the result of incapability of supplying the print liquid to the chip head.
It is a further object of the present invention to provide a liquid ejecting head unit wherein the gas passing through the filling material does not enter the downstream side of the porous member with respect to the direction of the flow of the print liquid, and the supply passage of the print liquid is not easily blocked by the bubbles stagnating at the downstream side of the porous member.
According to an aspect of the present invention, there is provided a liquid ejecting head unit comprising: a chip head comprising a plurality of ejection outlets for ejecting droplets; a plurality of flow paths in fluid communication with said ejection outlets, respectively; a first common liquid chamber for supplying the liquid to said flow paths; a supply member having a liquid supply path for supplying the liquid to first common liquid chamber; energy generating elements, provided in the flow paths for generating energy for ejecting the droplets; a unit frame having a second common liquid chamber for accommodating the liquid to be supplied to said supply member, said unit frame being connected with said chip head; a porous member provided between the liquid supply path of said chip head-and said second common liquid chamber of said unit frame; wherein a connecting portion between said chip head and said unit frame is disposed upstream of said porous member with respect to a direction of flow of the liquid from said second common liquid chamber to said liquid supply path through said porous member; wherein said porous member is inclined relative to the liquid flow direction.
With this structure, the bubble generated during the liquid ejecting operation moves toward upstream to reach to the porous member, and are trapped by the porous member. Since the porous member is inclined relative to the direction of the flow of the liquid, the bubbles are trapped at one side of the porous member so that contact of the liquid to the porous member is maintained at the other side of the porous member. Thus, it is easy to assure the flow of the liquid to the supply member through the porous member from the second common liquid chamber, so that frequency of the refreshing operations can be reduced, thus avoiding the decrease of the print liquid use efficiency and the reduction of the printing speed.
Additionally, since the porous member is inclined with respect to the liquid flow direction, the area of the porous member can be made larger than a cross-sectional area (perpendicular to the flow path direction in the liquid supply path) at the position where the porous member o the liquid supply path is disposed. This improves the collection efficiency of the coagulation or the like by the porous member and the transmission efficiency of the liquid by the porous member as compared with the case where the porous member is perpendicular to the liquid flow direction.
Since the connecting portion between the chip head and the unit frame is disposed upstream of the porous member with respect to the liquid flow direction, the ambient air having passed through the filling material does not come to the supply member side of the chip head. Therefore, the clogging of the nozzles of the chip head by the coagulation can be avoided. The ambient air having passed through the filling material may come to the second common liquid chamber side, but the air in the second common liquid chamber is discharged into the ambience sooner or later.
According to another aspect of the present invention, there is provided the direction is substantially vertical.
According to a further aspect of the present invention, there is provided a cross-sectional area of the liquid supply path is maximum at a portion thereof having the porous member.
According to this feature, the area of the porous member which is effective to trap the bubbles is large, so that flow of the liquid from the second common liquid chamber through the porous member to the supply member can be further assured. Therefore, the frequency of the refreshing operations can be reduce.
According to a further aspect of the present invention, there is provided the connecting portion is sealed by a filling material.
According to a further aspect of the present invention, there is provided a liquid ejecting head unit comprising: a chip head comprising a plurality of ejection outlets for ejecting droplets; a plurality of flow paths in fluid communication with the ejection outlets, respectively; a first common liquid chamber for supplying the liquid to the flow paths; a supply member having a liquid supply path for supplying the liquid to first common liquid chamber; energy generating elements, provided in the flow paths for generating energy for ejecting the droplets; a unit frame having a second common liquid chamber for accommodating the liquid to be supplied to the supply member, the unit frame being connected with the chip head; a porous member provided between the liquid supply path of the chip head and the second common liquid chamber of the unit frame; wherein a connecting portion between the chip head and the unit frame is disposed upstream of the porous member with respect to a direction of flow of the liquid from the second common liquid chamber to the liquid supply path through the porous member; wherein the connecting portion is sealed by a filling material.
With this structure, the ambient air having passed through the filling material does not entering the supply member side of the chip head, the clogging of the nozzle of the chip head by the coagulation resulting from the bubble can be prevented.
According to a further aspect of the present invention, there is provided a liquid ejecting head unit comprising; an element substrate having, on a surface thereof, a plurality of juxtaposed energy generating elements for applying ejection energy to the liquid; a top plate forming a plurality of liquid flow paths in fluid communication with ejection outlets for ejecting the liquid, corresponding to the energy generating elements, respectively, the top plate forming a first common liquid chamber in fluid communication with the liquid flow paths; a container chip having a supply passage for supplying the liquid to the liquid flow path and the first common liquid chamber: a frame having a second common liquid chamber, connected to the container chip, for supplying the liquid to the supply passage, wherein a first connection surface of the container chip at which the container chip is connected to the frame includes a first inclined surface which is inclined relative to a reference surface in a wall surface forming the supply passage and which is provided with a first opening which is open to the supply passage, and wherein a second connection surface of the frame at which the frame is connected to the first connection surface includes a second inclined surface which is inclined relative to the reference surface when the container chip and the frame are connected to each other and which is provided with a second opening corresponding the opening of the supply passage and having substantially same area as the first opening.
With this structure, the frame is provided with the second common liquid chamber so that required amount of the liquid can be fed into the container chip even when a large amount of the liquid is consumed. Since the first opening of the supply passage and the second opening of the second common liquid chamber are formed in the first inclined surface and the second inclined surface which are inclined relative to the reference surface of the wall surface forming the supply passage, the cross-sectional area can be made large as compared with an opening formed in a surface perpendicular to the reference surface. Since the areas of the first opening and the second opening are substantially the same, there is no abrupt change of the cross-sectional area of the passage in the connection between the openings.
According to a further aspect of the present invention, there is provided the first connection surface has a first vertical surface which is substantially perpendicular relative to the reference surface.
According to a further aspect of the present invention, there is provided the first connection surface has a first horizontal surface which is substantially horizontal relative to the reference surface.
According to a further aspect of the present invention, there is provided the second connection surface has a second vertical surface which is substantially perpendicular relative to the reference surface when the container chip and the frame are connected to each other and which is connected to the first vertical surface.
According to a further aspect of the present invention, there is provided the second connection surface has a second horizontal surface which is substantially horizontal relative to the reference surface which the container chip and the frame are connection to each other and which is connected to the first horizontal surface.
According to a further aspect of the present invention, there is provided the first vertical surface and the second vertical surface are provided with positioning portions for positioning relative to the first opening and the second opening.
According to a further aspect of the present invention, there is provided the first horizontal surface and the second horizontal surface are provided with positioning portions for positioning relative to the first opening and the second opening.
According to a further aspect of the present invention, there is provided the frame constitutes a liquid container for containing therein the liquid, which forms the second common liquid chamber which is a substantial hermetically sealed space except for the second opening.
According to a further aspect of the present invention, there is provided the liquid container has a negative pressure producing member for generating a negative pressure therein.
According to a further aspect of the present invention, it comprises a filter between the first opening and second opening, and a connecting portion for between the first connection surface and the second connection surface upstream of the filter with respect to the liquid flow direction from the second common liquid chamber to the first common liquid chamber, wherein at the connecting portion, the first connection surface and the second connection surface are connected with each other by a filling material.
According to a further aspect of the present invention, there is provided the supply passage has a maximum cross-sectional area at the first opening, and has a region in which a cross-sectional area thereof increases toward the first opening.
Since the first connection surface and the second connection surface have the first inclined surface and the second inclined surface, the space for receiving the filling material is as large as that when the filling material is filled to only the perpendicular surface (perpendicular to the reference surface), and therefore, there is no need of increasing the thicknesses around the openings of the container chip and the frame, so that thicknesses of the container chip and the frame can be reused.
According to a further aspect of the present invention, there is provided the first inclined surface and the second inclined surface are substantially parallel when the container chip and the frame are connected to each other.
According to a further aspect of the present invention, there is provided the first inclined surface and the second inclined surface are non-parallel relative to each other when the container chip and the frame are connected to each other.
According to a further aspect of the present invention, it comprises a step of imparting a relative movement between the first inclined surface and the second inclined surface to position the first opening and the second opening.
Since when the container chip and the frame are connected to each other, the first inclined surface of the container chip and the second inclined surface of the frame are abutted to each other, and the relative sliding is imparted therebetween, so that container chip and the frame can be correctly positioned to each other using self-alignment.
According to a further aspect of the present invention, it comprises a step of forming the first inclination surface and the second inclination surface such that gap which is formed between the first inclined surface and the second inclination surface when the container chip and the frame are connected, generally converges in a direction of infiltration of the filling material; a step of imparting a relative movement between the first inclined surface and the second inclined surface to position the first opening and the second opening; the filling material is injected into the converging gap from a wider side.
With this feature, filling material is supplied into between the first inclined surface and the second inclined surface from the side where the distance between the first inclined surface and the second inclined surface is large, go that surface tension can be efficiently utilized to fill the filling material, the surface tension being produced between the first inclined surface and the filling material and between the second inclined surface and the filling material. Particularly, in that case that there is a position where the cross-sectional area of the first opening is the maximum and the cross-sectional area is enlarged toward the first opening, the area of the first inclined surface and the second inclined inclined surface are larger than the maximum cross-sectional area of the first opening. Therefore, the size between the first inclined surface and second inclined surface relative to the size of the needle for injecting the filling material is proper, so that operativity when the filling material is filled is improved.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present intention taken in conjunction with the accompanying drawings.